Do they bloom a different color or not at all? If they bloom pinky, then you are out of luck, that is their color. If they don't bloom at all, they probably need more sun.

I have the Royal Red Butterfly bush and it's actual bloom color is more of a magenta red. I don't think I have ever seen a true red butterfly bush or a true red Rose of Sharon. Lots of plants that are labeled as Red Flowering are actually just in the red family and could actually go from one end of the spectrum to the other.

Penny

Here is a link that might be useful: Royal Red Butterfly Bush